Youth is wasted on the young.

If history repeats itself, and the unexpected always happens, how incapable must Man be of learning from experience.

A fool's brain digests philosophy into folly, science into superstition, and art into pedantry. Hence University education.

I would like to take you seriously, but to do so would be an affront to your intelligence.

When I see these kids 6 years old with a private coach, and at 7, they have a fitness coach, I'm like, 'Aw, come on.' At 12, it's for sure they will lose all the interest in tennis because they do not interact with other kids.

The only way you can get match fitness is by playing games.

When our weaknesses affect health and friendship, we are very much aware of their existence.

You can exercise right through to your 60s, 70s, 80s and even 90s.